Day_28_RegEx,_Patterns,_and_Intro_to_Databases.cpp

#include <bits/stdc++.h>

using namespace std;

vector<string> split_string(string);
vector<string> name;


int main()
{
	int N;
	cin >> N;
	cin.ignore(numeric_limits<streamsize>::max(), '\n');

	for (int N_itr = 0; N_itr < N; N_itr++) {
		string firstNameEmailID_temp;
		getline(cin, firstNameEmailID_temp);

		vector<string> firstNameEmailID = split_string(firstNameEmailID_temp);

		string firstName = firstNameEmailID[0];

		string emailID = firstNameEmailID[1];

		string id = "";
		string mail = "";
		bool flag = false;
		for (int i = 0; i<emailID.length(); i++) {
			if (emailID[i] == '@') flag = true;
			if (flag) mail += emailID[i];
		}
		if (mail == "@gmail.com") name.push_back(firstName);
	}
	sort(name.begin(), name.end());

	for (int i = 0; i<name.size(); i++) {
		cout << name[i] << '\n';
	}

	return 0;
}

vector<string> split_string(string input_string) {
	string::iterator new_end = unique(input_string.begin(), input_string.end(), [](const char &x, const char &y) {
		return x == y and x == ' ';
	});

	input_string.erase(new_end, input_string.end());

	while (input_string[input_string.length() - 1] == ' ') {
		input_string.pop_back();
	}

	vector<string> splits;
	char delimiter = ' ';

	size_t i = 0;
	size_t pos = input_string.find(delimiter);

	while (pos != string::npos) {
		splits.push_back(input_string.substr(i, pos - i));

		i = pos + 1;
		pos = input_string.find(delimiter, i);
	}

	splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));

	return splits;
}